Bead wire manufacturing method and manufacturing apparatus

ABSTRACT

A bead wire manufacturing method/apparatus includes a descaling step/device for removing oxide on the surface of a wire rod, a coating liquid adhesion step/device for adhering a coating liquid to the wire rod, wiredrawing steps/devices for performing area reduction workings on the wire rod, and a bluing step/device for bluing the wire rod having been raised to a high temperature through the area reduction workings, in a temperature range of 350° C. to 480° C. Thus, the wire rod having been raised to a high temperature through wiredrawing is blued without being cooled down to effectively utilize the temperature retained therein, so that the method/apparatus is little in energy loss.

TECHNICAL FIELD

The present invention relates to a manufacturing method and a manufacturing apparatus for manufacturing bead wires used in automotive tyres.

BACKGROUND ART

A manufacturing process for bead wires which are used in the production of bead cores as reinforcements in automotive tyres comprises a wiredrawing line and a plating line. Specifically, it comprises a wiredrawing line in which a rolled wire rod with micro pearlite structures having been subjected to a patenting treatment is wiredrawn to a predetermined wire diameter by repeating a wiredrawing and a patenting treatment, and a plating line in which the wire rod having been wiredrawn to the predetermined wire diameter is given a bluing treatment to recapture the ductility therein and is further given a plating on the surface thereof with cupper, bronze, brass or the like for a bead wire. For example, Patent Document 1 and Patent Document 2 describe manufacturing methods and manufacturing apparatuses for bead wires (wire rods) of this kind.

FIG. 6 shows a prior art manufacturing process for bead wires. In a wiredrawing line L1, a wire rod uncoiled from a supply stand 1 has oxide film removed from its surface at a descaling step 2 and then, is made to pass through a coating liquid adhesion step 3 to adhere lubrication coating liquid to the surface thereof. Thereafter, an area reduction working and a cooling are repeated through a plurality of wiredrawing steps 4 each including an area reduction working step 4 a and a cooling step 4 b, and the wire rod having been machined to be reduced in area to a predetermined wire diameter is coiled by a coiler 5.

Further, in the plating line L2, the wire rod which was wiredrawn in the wiredrawing line L1 to the predetermined wire diameter is uncoiled from a supply stand 1, is blued at a bluing step 6, and then, scales which have been adhered to the surface of the wire rod through the bluing are removed at an acid pickling step 7 a. The wire rod is water washed at a water washing step 7 b, thereafter is subjected to a plating treatment with copper, bronze, zinc, brass or the like at a plating step 8, and then, is coiled by a coiler 5 after passing through a water washing step 7 c and a hot water washing step 7 d, whereby a bead wire for tyres is manufactured.

PRIOR ART DOCUMENTS Patent Documents

-   Patent Document 1: JP2008-284581 A -   Patent Document 2: JP6-2049 A

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

Generally, a wiredrawing line is constructed to process wire rods one by one, whereas a plating line is constructed to treat wiredrawn wire rods simultaneously by a unit of twenty to thirty-something in view of equipment cost and productivity. Accordingly, in the plating line, the wire rods in the number of twenty to thirty-something are uncoiled from coilers and are fed to pass through a bluing step and a plating step to be wound by coilers thereafter. For this reason, there is required a large-scale bluing facility which has a capability of keeping the wires rods of twenty to thirty-something in a temperature range of 350° C. to 480° C. This causes the expense to the facility to rise as well as causes wastefulness that substantially the same energy is consumed even where wire rods of a fewer number are treated due to a decrease in production volume.

In addition, there is a possibility that a lead bath, a salt bath, a fluidized bed or the like at the bluing step breaks with a large change in temperature. Further, once the temperature of the bath is lowered, much time and cost are taken to bring the bath into a predetermined temperature range required for bluing. Therefore, the bath should be maintained at a high temperature while the line is out of operation, which is very wasteful. Moreover, a further wastefulness resides in that though being raised in temperature by being wiredrawn, a wire rod is cooled down to be coiled by a coiler, and thereafter, the wire rod at around the room temperature is uncoiled from a coiler and is heated to the temperature range of 350° C. to 480° C. for bluing.

The present invention has been made in order to solve the foregoing problems in the prior art, and an object thereof is to provide bead wire manufacturing method and manufacturing apparatus which are capable of effectively utilizing the temperature retained in a wire rod by performing a bluing without cooling down the wire rod having been raised by wiredrawing to a high temperature and which are little in energy loss.

Measures for Solving the Problems

The feature of the invention in a bead wire manufacturing method according to Claim 1 resides in comprising a descaling step of removing oxide on the surface of a wire rod, a coating liquid adhesion step of adhering a coating liquid to the wire rod from which the oxide has been removed, wiredrawing steps of performing area reduction workings on the wire rod with the coating liquid adhered thereto, and a bluing step of bluing the wire rod having been raised to a high temperature through the area reduction working, in a temperature range of 350° C. to 480° C.

The feature of the invention in the bead wire manufacturing method according to Claim 2 resides in that in Claim 1, the wiredrawing steps comprise area reduction steps of performing the area reduction workings by wiredrawing the wire rod and cooling steps of cooling the wire rod having been subjected to the area reduction workings and that the cooling step is omitted from the wiredrawing step right before the bluing step.

The feature of the invention in the bead wire manufacturing method according to Claim 3 resides in that in Claim 1 or 2, the method further comprises a plating step of plating the wire rod having been blued at the bluing step.

The feature of the invention in the bead wire manufacturing method according to Claim 4 resides in that in any one of Claims 1 to 3, the wire rod is made of a high carbon steel containing carbon in a range of 0.59°% or more to 1.1% or less in weight percent and having two-phase structures of ferrite and cementite.

The feature of the invention in a bead wire manufacturing apparatus according to Claim 5 resides in comprising a wiredrawing line for wiredrawing a wire rod made of a high carbon steel to a predetermined wire diameter suitable for bead wire and a plating line for plating the wire rod having been wiredrawn to the predetermined diameter, wherein the wiredrawing line comprises a descaling device for removing oxide on the surface of the wire rod, a coating liquid adhesion device for adhering a coating liquid to the wire rod, wiredrawing devices for performing area reduction workings on the wire rod, and a bluing device for bluing the wire rod having been raised to a high temperature through the area reduction working, in a temperature range of 350° C. to 480° C.

The feature of the invention in the bead wire manufacturing apparatus according to Claim 6 resides in that in Claim 5, the wiredrawing line is constructed to process the wire rods one by one, while the plating line is constructed to process the wire rods having been wiredrawn by the wiredrawing line, simultaneously by a unit of several tens.

The feature of the invention in the bead wire manufacturing apparatus according to Claim 7 resides in that in Claim 5 or 6, the bluing device is provided with a heating device for heating to the temperature range the wire rod having been raised to the high temperature through the area reduction working.

The feature of the invention in the bead wire manufacturing apparatus according to Claim 8 resides in that in Claim 7, the heating device is provided with a rotatable heating drum for winding therearound the wire rod having been raised to the high temperature through the area reduction working and a heating coil built in the heating drum for heating the wire rod having been wound around the heating drum.

The feature of the invention in the bead wire manufacturing apparatus according to Claim 9 resides in that in Claim 7, the heating device is provided with a heating furnace for performing an electric current heating or an induction heating on the wire rod having been heated through the wiredrawing.

Effects of the Invention

In the invention of the bead wire manufacturing method according to Claim 1, since the bluing step is provided for bluing the wire rod, having been raised to the high temperature through the area reduction working at the wiredrawing step, in the temperature range of 350° C. to 480° C., it is possible to perform the bluing by effectively utilizing the working-generated heat retained in the wire rod having been raised to the high temperature through the area reduction working, so that the bluing can be done efficiently at a little energy loss.

In the invention of the bead wire manufacturing method according to Claim 2, the wiredrawing steps comprise the area reduction working steps of performing the area reduction workings by wiredrawing the wire rod and the cooling steps of cooling the wire rod having been subjected to the area reduction workings, and the cooling step is omitted from the wiredrawing step right before the bluing step. Thus, the wire rod having been raised to the high temperature through the area reduction working at the area reduction working step can be cooled to be sent out to the next area reduction working step, so that the wire rod can be restrained from becoming fragile. Additionally, since the wire rod having been raised to the high temperature through the area reduction working is sent to the bluing step as it is at the high temperature without being cooled down, the bluing can be done by effectively utilizing the working-generated heat retained in the wire rod.

In the invention of the bead wire manufacturing method according to Claim 3, since the method further comprises the plating step of plating the wire rod having been blued at the bluing step, the adhesion force of a bead wire with surrounding rubber can be enhanced thanks to the plating on the wire rod.

In the invention of the bead wire manufacturing method according to Claim 4, the wire rod is made of the high carbon steel containing carbon in the range of 0.59% or more to 1.1% or less in weight percent and having the two-phase structures of ferrite and cementite. Thus, a tensile strength required for bead wires can be secured through the area reduction workings at the wiredrawing steps.

In the invention of the bead wire manufacturing apparatus according to Claim 5, the wiredrawing line is provided with the bluing device for bluing in the temperature range of 350° C. to 480° C. the wire rod having been raised to the high temperature through the area reduction working by the wiredrawing device. Thus, the bluing can be done by effectively utilizing the working-generated heat retained in the wire rod which has been raised to the high temperature through the area reduction working by the wiredrawing device, so that the bead wire manufacturing apparatus being small in energy loss can be realized.

In the invention of the bead wire manufacturing apparatus according to Claim 6, the wiredrawing line is constructed to process the wire rods one by one, while the plating line is constructed to process the wire rods having been wiredrawn in the wiredrawing line, simultaneously by a unit of several tens. Thus, the bluing device is sufficient to be a small and simple device which is required to blue one wire rod only, so that the cost taken for the bluing can be reduced.

In the invention of the bead wire manufacturing apparatus according to Claim 7, the bluing device is provided with the heating device for heating the wire rod having been raised to the high temperature through the area reduction working, up to the temperature range of 350° C. to 480° C. Thus, the heating device is sufficient to be a small and simple device which is required to blue one wire rod only, so that the cost taken for the bluing can be reduced, and hence, that the facility expense for the bead wire manufacturing apparatus can be reduced.

In the invention of the bead wire manufacturing apparatus according to Claim 8, the heating device is provided with the rotatable heating drum for winding therearound the wire rod having been raised to the high temperature through the area reduction working and the heating coil built in the heating drum for heating the wire rod having been wound around the heating drum. Thus, the wire rod having been raised to the high temperature through the area reduction working can easily be heated up to the predetermined temperature by the heating drum which has been heated by the heating coil.

In the invention of the bead wire manufacturing apparatus according to Claim 9, the heating device is provided with the heating furnace for performing the electric current heating or the induction heating on the wire rod having been heated through the wiredrawing. Thus, the wire rod having been raised to the high temperature through the area reduction working can easily be heated by the small and simple heating furnace to the predetermined temperature.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a process chart showing a manufacturing process for manufacturing bead wires in one embodiment according to the present invention.

FIG. 2 is an external view showing respective one examples of wiredrawing devices and a bluing device.

FIG. 3 is a sectional view showing specific examples of the wiredrawing devices and the bluing device.

FIG. 4 is a sectional view taken along the line 4-4 in FIG. 3.

FIG. 5 is a sectional view showing specific examples of a wiredrawing device and a bluing device in a second embodiment according to the present invention.

FIG. 6 is a process chart showing a bead wire manufacturing method in the prior art.

Forms for Implementing the Invention

Hereinafter, description will be made regarding a bead wire manufacturing method and a manufacturing apparatus therefor in an embodiment of the present invention.

FIG. 1 shows a manufacturer process for manufacturing bead wires. The manufacturing process comprises a wiredrawing line L1 for wiredrawing a wire rod made of a high carbon steel to a predetermined wire diameter suitable for bead wires and a plating line L2 for plating the wire rod which has been wiredrawn to the predetermined diameter.

In the wiredrawing line L1, the wire rod made of the high carbon steel which is uncoiled from a supply stand 11 is subjected to a descaling step 12 to remove an oxide film from its surface, then is made to pass through a coating liquid adhesion step 13 to adhere lubrication coating liquid to the surface of the wire rod, and thereafter, is made to pass through a drying furnace (not shown) for drying the lubrication coating liquid. Subsequently, through a plurality of dry wiredrawing steps 16 each of which is provided with an area reduction working step 14 and a cooling step 15, an area reduction working is repeated, whereby the wire rod is machined to be reduced in area to a predetermined wire diameter suitable for bead wires. Thereafter, in order to recapture the ductility in the wiredrawn wire rod, a bluing is carried out at a bluing step 17 in a temperature range of 350° C. to 480° C. The wire rod heated to the predetermined temperature range through the bluing is cooled down at a cooling step 18 to a temperature close to the room temperature for coiling and is wound by a coiler 19 into a coil fashion.

At this time, when the wire rod is subjected to the area reduction working at the area reduction working step 14 of the wiredrawing step 16, the wire rod rises to a high temperature due to working-generated heat. If the area reduction working were repeated at such a high temperature, the wire rod would become hard and fragile and hence would become easier to break. Therefore, the rod wire at a high temperature is cooled at a cooling step 15 and is fed to the next wiredrawing step 16. However, at a final wiredrawing step 16, in other words, at a wiredrawing step 16 just before the bluing step 17, the cooling step 15 is omitted. As a result, the wire rod on which the area reduction working was carried out at the final wiredrawing step 16 is fed to the bluing step 17 as it is at the high temperature without being cooled down, and is blued in the temperature range of 350 to 480° C.

In the present embodiment, as one example, a raw material for bead wire is made of a high carbon steel containing carbon in a range of 0.59% or more through 1.1% or less in weight percent and having two-phase structures of ferrite and cementite. Then, the high carbon steel wire of a diameter in a range of 5.5-6.5 mm for example is wiredrawn to a final wire diameter in a range of 2.20-0.94 mm in diameter suitable for bead wire by being repetitively subjected to the area reduction workings in the wiredrawing line L1.

In the plating line L2, on the other hand, the wire rod which has been wiredrawn to the predetermined diameter and has been blued in the wiredrawing line L1 is uncoiled from a supply stand 21. The scale adhered to the surface of the wire rod through the aforementioned bluing is removed at an acid pickling step 22, and the wire rod is water washed at a water washing step 23. Subsequently, for a higher adhesion force to surrounding rubber, a bronze plating of, for example, Cu/Sn=93/7 is carried out at a plating step 24. Thereafter, the wire rod is fed to pass through an water washing step 25 and a hot-water washing step 26 and is coiled into a coiler 27 as a bead wire, whereby the bead wire is manufactured.

The descaling step 12, the coating liquid adhesion step 13, the area reduction working steps 14, the cooling steps 15, the wiredrawing steps 16, the bluing step 17, the cooling step 18, the acid pickling step 22, the water washing step 23, the plating step 24, the water washing step 25, and the hot-water washing step 26 which are all aforementioned constitute a descaling device, a coating liquid adhesion device, area reduction working devices, cooling devices, wiredrawing devices, a bluing device, a cooling device, an acid pickling tub, a water washing tub, a plating tub, a water washing tub, and a hot-water washing tub in the bead wire manufacturing apparatus, respectively.

In the aforementioned wiredrawing line L1, the wire rods are processed one by one, whereas in the plating line L2, the wire rods which were wiredrawn in the wiredrawing line L1 are simultaneously processed by a unit of twenty to thirty-something, that is, by a unit of several tens. As the wiredrawing line L1, a plurality of lines may be arranged, if need be.

According to the present embodiment in which the bluing is processed in the wiredrawing line L1, the bluing step 17 can use a small and simple equipment which is required to blue one wire rod. In addition, since the wire rod which has risen to a high temperature through the area reduction working at the final wiredrawing step 16 is fed to the bluing step 17 as it is at the high temperature without being cooled down, the bluing of the wire rod can be done by effectively utilizing the working-generated heat generated through the area reduction working. Therefore, it becomes possible to carry out the bluing efficiently at a little energy loss.

FIGS. 2 and 3 show specific examples of the wiredrawing devices 16 and the bluing device 17 in the wiredrawing line L1. Because of rising to a high temperature through the area reduction working, the wire rod W which has been subjected to the area reduction working by the area reduction working device 14 with a die is spirally wound around, and in contact with, the outer circumference of a rotatable cooling drum 31 (refer to FIG. 3) constituting the cooling device 15 by a predetermined number of turns. As a result, the wire rod W is cooled down to a temperature close to the room temperature through the heat exchange function between itself and the cooling drum 31.

The wire rod W cooled down by the cooling device 15 is fed to the next wiredrawing device 16 to have the area reduction working repetitively carried out thereon. And, the wire rod W on which the area reduction working has been carried out by the final wiredrawing device 16 to the final diameter is fed to a heating device 40 constituting the bluing device 17, as a shown in FIG. 3, and is heated to a temperature (in a range of 350 to 480° C.) suitable for bluing. That is, the wire rod W which has risen to the high temperature through the area reduction working by the final wiredrawing device 16 is fed to the bluing device 17 as it is at the high temperature without being cooled down.

As shown in FIG. 3, the heating device 40 is provided with a heating drum 41 taking a ring shape, and the wire rod W fed from the final wiredrawing device 16 is spirally wound around, and in contact with, the outer circumference of the heating drum 41 by a predetermined number of turns. A rotational shaft 42 is connected to a lower end of the heating drum 41 concentrically with the heating drum 41. The rotational shaft 42 is rotatably supported in a support table 44 through bearings 43 about a vertical axis. A gear 45A is fixed on the rotational shaft 42, and a drive motor 46 is connected to a gear 45B meshing with the gear 45A, so that the heating drum 41 is rotationally driven by the drive motor 46.

As shown in FIG. 4, the heating drum 41 has a plurality of heater coils 47 built (embeded) therein to be arranged on a circumference thereof, and these heater coils 47 are connected to a conductive cable (not shown) passing through the rotational shaft 42 and is connected to a heater power supply through a slip spring 48. Thus, the heater coils 47 are heated by the heater power supply, and the heating drum 41 is heated by the heater coils 47. Therefore, the wire rod W can be heated to a predetermined temperature suitable for bluing through the heat exchange function between the heating drum 41 and the wire rod W which is spirally wound around the circumference of the heating drum 41. The heating temperature conveyed to the wire rod W can be controlled in dependence on the number of turns of the wire rod W around the heating drum 41 as well as on the time during which it is held turned therearound.

In this case, since the heating device 40 constituting the bluing device 17 suffices to be a small and simple device which is required to blue one wire rod, the bluing can be done by the heating device 40 being low in cost. Furthermore, the wire rod W which has risen to the high temperature through the area reduction working by the final wiredrawing device 16 is fed to the heating device 40 (the bluing device 17) as it is at the high temperature without being cooled down. As a result, the amount of heat that is required to heat the wire rod W up to the temperature suitable for bluing suffices to be a little. In this manner, since the bluing can be done by effectively utilizing the working-generated heat retained in the wire rod W, it can be realized to carry out the bluing efficiently at a little energy loss.

Numeral 49 in FIG. 3 denotes heat insulation means for insulating the heating drum 41 so that heat therefrom is not conveyed to the bearings 43 supporting the rotational shaft 42. The heat insulation means 49 can be constructed as, for example, means for supplying cooling water to a boundary portion between the heating drum 41 and the rotational shaft 42.

On the other hand, as shown in FIG. 3, the cooling drum 31 of the cooling device 15 takes a ring shape, and a rotational shaft 32 connected to a lower end of the cooling drum 31 is rotatably supported in a support table 34 through bearings 33 about a vertical axis. A gear 35 A is fixed on the rotational shaft 32, and a drive motor 36 is connected to a gear 35B meshing with the gear 35A, so that the cooling drum 31 can be rotationally driven by the drive motor 36.

The cooling drum 31 has a cooling space portion 37 taking an annular shape, for example, and the cooling space portion 37 is formed to be supplied with a cooling medium such as water or the like. The cooling drum 31 is cooled down by the cooling medium supplied to the cooling space portion 37, so that the wire rod W is cooled down to a temperature close to the room temperature through the heat exchange function between the cooling drum 31 and the high temperature wire rod W spirally wounded around the outer circumference of the cooling drum 31. The cooling temperature conveyed to the wire rod W can be controlled in dependence on the number of turns of the wire rod W around the cooling drum 31 as well as on the time during which it is held turned therearound.

The wire rod W having been heated through the bluing is cooled down by the cooling device 18 (refer to FIG. 2) for coiling into the coiler 19. The cooling device 18 is constructed by a cooling drum which is similar to the cooling device 15 shown in FIG. 3. A rotational shaft for the cooling drum in this device suffices to be one that is rotatable freely only.

In the construction described above, when the cooling drums 31 and the heating drum 41 are rotationally driven by the drive motors 36, 46 of the cooling devices 15 and the bluing device 17, the wire rod W flowing in the wiredrawing line L1 is drawn, and the wire rod W having risen to high temperatures through the area reduction working at each of the wiredrawing devices 16 is spirally wounded around the outer circumferences of the cooling drums 31 and the outer circumference of the heating drum 41. The wire rod W past the bluing device 17 is coiled into the coiler 19 through the winding action by the coiler 19.

As a result, the wire rod W having risen to high temperatures through the area reduction working at each area reduction working device 14 is cooled down by each cooling drum 31 and is fed to the next area reduction working device 14, while the wire rod W having risen to a high temperature through the area reduction working at the final area reduction device 14 is heated by the heating drum 41 to be blued in the temperature range of 350 to 480° C.

According to the aforementioned first embodiment, the wire rod W having been subjected to the area reduction working by the final wiredrawing device 16, in other words, by the wiredrawing device 16 just before the bluing device 17 is blued by being fed to the bluing device 17 as it is at the high temperature without being cooled down. Thus, the heating device 40 constituting the bluing device 17 suffices to be a small and simple device which is required to blue one wire rod. In addition, the bluing can be done by effectively utilizing the working-generated heat that is retained in the wire rod W having risen to the high temperature through the area reduction working at the final wiredrawing device 16, and therefore, it is possible to carry out the bluing efficiently at a little energy loss.

FIG. 5 shows a second embodiment according to the present invention. It differs from the first embodiment in that while the wire rod W in the first embodiment is heated and blued by being wound around the outer circumference of the heating drum 41, the wire rod W in the second embodiment is blued by passing through a heating device comprising a heating furnace 50 for electric current heating or induction heating. In this connection, the second embodiment also differs in that since it is unable to draw the wire rod W as the heating drum 41 in the bluing device 17 does, a cooling device 18 for cooling down the blued wire rod W is given a function of drawing the wire rod W. The second embodiment is the same as the first embodiment in other respects. Therefore, the following description will be mainly made regarding the respects in which the second embodiment differs from the first embodiment, and description of the same components will be omitted as being designated by the same reference numerals.

That is, in the second embodiment, as shown in FIG. 5, the wire rod W which has been subjected to the area reduction working to a final diameter by a final wiredrawing device 16 is heated to a temperature range of 350 to 480° C. to be blued as a result of being made to pass at a predetermined speed through the heating device comprising the heating furnace 50 for electric current heating or induction heating.

Further, like the cooling device 15 described in the aforementioned first embodiment, a cooling device 18 for cooling the wire rod W having been blued is provided with a cooling drum 31 taking a ring shape, and the wire rod W is spirally wound around, and in contact with, the outer circumference of the cooling drum 31. A rotational shaft 32 is concentrically connected to the lower end of the cooling drum 31 and is rotatably supported in a support table 34 through bearings 33 about a vertical axis. A gear 35A is fixed on the rotational shaft 32, and a drive motor 36 is connected to a gear 35B meshing with the gear 35A, so that the cooling drum 31 is rotationally driven by the drive motor 36.

A cooling space portion 37 is formed in the cooling drum 31, and a cooling medium such as water or the like is supplied to the cooling space portion 37 to cool down the cooling drum 31. Therefore, the wire rod W is cooled down to a temperature close to the room temperature through the heat exchange function between the cooling drum 31 and the high temperature wire rod W which is spirally wound around the outer circumference of the cooling drum 31.

In the second embodiment, by rotationally driving the cooling drums 31 by the drive motors 36 of the cooling devices 15, 18, the wire rod W passing through the wiredrawing line L1 is drawn and is fed to pass at a predetermined speed through the heating furnace 50 for electric current heating or induction heating, whereby the wire rod W is blued. The blued wire rod W is spirally wound around the cooling drum 31 of the cooling device 18, and heat exchange is carried out between the cooling drum 31 and the blued wire rod W. Consequently, the wire rod W having been heated by the heating furnace 50 is cooled down.

Also in the aforementioned second embodiment, as mentioned earlier in the first embodiment, the heating furnace 50 which performs the electric current heating or the induction heating on the wire rod W for bluing suffices to be a small and simple device that is required to blue one wire rod. In addition, the bluing can be done by effectively utilizing the working-generated heat that is retained in the wire rod W having risen to the high temperature through the area reduction working, and therefore, it becomes possible to perform the bluing efficiently at a little energy loss.

In the aforementioned embodiments, description has been made regarding the example that the blued wire rod is bronze-plated. However, besides the bronze-plating, the plating can be done as zinc-plating, copper-plating, brass-plating or the like.

Furthermore, in the aforementioned embodiments, description has been made regarding the example that the cooling devices 15 (18) are constructed by the cooling drums 31 and that the heating device 40 constituting the bluing device 17 is constructed by the heating drum 41 or the heating furnace 50 such as electric current heating furnace, induction heating furnace or the like. However, the present invention is not necessarily limited to the constructions described in the embodiments.

As described above, the present invention has been described based on the embodiments. However, the present invention is not limited to the constructions described in the embodiments and can take various forms without departing from the gist of the present invention described in the patent claims.

INDUSTRIAL APPLICABILITY

Bead wire manufacturing method and manufacturing apparatus according to the present invention are suitable for manufacturing bead wires which are used in producing bead cores being reinforcements for automotive tyres.

DESCRIPTION OF SYMBOLS

12 . . . descaling step (descaling device), 13 . . . coating liquid adhesion step (coating liquid adhesion device), 14 . . . area reduction working step (area reduction working device), 15,18 . . . cooling step (cooling device), 16 . . . wiredrawing step (wiredrawing device), 17 . . . bluing step (bluing device), 24 . . . plating step (plating tub), 31 . . . cooling drum, 40 . . . heating device, 41 . . . heating drum, 50 . . . heating furnace, W . . . wire rod 

1-9. (canceled)
 10. A bead wire manufacturing method comprising: a descaling step of removing oxide on the surface of a wire rod; a coating liquid adhesion step of adhering a coating liquid to the wire rod from which the oxide has been removed; wiredrawing steps of performing area reduction workings on the wire rod with the coating liquid adhered thereto; and a bluing step of bluing the wire rod having been raised to a high temperature through the area reduction working, in a temperature range of 350° C. to 480° C.
 11. The bead wire manufacturing method in claim 10, wherein: the wiredrawing steps comprise area reduction steps of performing the area reduction workings by wiredrawing the wire rod and cooling steps of cooling the wire rod having been subjected to the area reduction workings, and the cooling step is omitted from the wiredrawing step right before the bluing step.
 12. The bead wire manufacturing method in claim 10, further comprising a plating step of plating the wire rod having been blued at the bluing step.
 13. The bead wire manufacturing method in claim 10, wherein the wire rod is made of a high carbon steel containing carbon in a range of 0.59% or more to 1.1% or less in weight percent and having two-phase structures of ferrite and cementite.
 14. A bead wire manufacturing apparatus comprising: a wiredrawing line for wiredrawing a wire rod made of a high carbon steel to a predetermined wire diameter suitable for bead wire; and a plating line for plating the wire rod having been wiredrawn to the predetermined diameter; wherein the wiredrawing line comprises: a descaling device for removing oxide on the surface of the wire rod; a coating liquid adhesion device for adhering a coating liquid to the wire rod; wiredrawing devices for performing area reduction workings on the wire rod; and a bluing device for bluing the wire rod having been raised to a high temperature through the area reduction working, in a temperature range of 350° C. to 480° C.
 15. The bead wire manufacturing apparatus in claim 14, wherein the wiredrawing line is constructed to process the wire rods one by one, while the plating line is constructed to process the wire rods having been wiredrawn by the wiredrawing line, simultaneously by a unit of plural tens.
 16. The bead wire manufacturing apparatus in claim 14, wherein the bluing device includes a heating device for heating to the temperature range the wire rod having been raised to the high temperature through the area reduction working.
 17. The bead wire manufacturing apparatus in claim 16, wherein the heating device includes a rotatable heating drum for winding therearound the wire rod having been raised to the high temperature through the area reduction working and a heating coil built in the heating drum for heating the wire rod having been wound around the heating drum.
 18. The bead wire manufacturing apparatus in claim 16, wherein the heating device includes a heating furnace for performing an electric current heating or an induction heating on the wire rod having been heated through the wiredrawing. 